& : Updates & Insights

Richard B. Ford, DVM, MS Emeritus Professor of Medicine Diplomate ACVIM and ACVPM (Hon) North Carolina State University Raleigh, North Carolina

In 1996 a group of academicians and feline practitioners met in an attempt to outline recommendations for implementing vaccination protocols in cats. At the time, we were concerned with a series of publications highlighting that, at least in some cats, feline leukemia and vaccines were causally associated with fibrosarcoma and death…a ‘adverse event’ that, at least to us, seemed unacceptable. If recommendations could be written that were consistent with good practices (and protection), yet requiring fewer vaccine doses over the lifetime of the cat, perhaps it would be possible to reduce the risk of what was being called at the time: Vaccine Associated Sarcoma, or VAS. This culminated in the first set of Guidelines, published in 1998, that included recommendations for administration of fewer doses of vaccine over the lifetime of the cat while introducing terms such as “core” vs. “non-core” and triennial vs. annual boosters.

Since 1998, various iterations of vaccination guidelines have been published for the dog and the cat. The focus has always been to develop recommendations, based on current science, which would support efforts by veterinarians to implement rational vaccination protocols in practice. What’s more, regional variations in infectious disease prevalence and vaccine availability have driven development of vaccination guidelines for the United Kingdom, Europe, and Asia, as well as North America. A task force has recently been formed to write companion guidelines for Latin America. Clearly, Vaccination Guidelines are going “global”.

While veterinarians are encouraged to incorporate published recommendations into vaccination protocols, there is no requirement to do so. These are simply recommendations. Rabies vaccination is the only exception…where rabies immunization laws are in place, veterinarians are expected to follow a vaccination protocol that is consistent with law.

This year’s manuscript includes a summary of current canine (2011) and feline (2013) vaccination guidelines for the US and Canada (see Tables 1 and 2), updates on new vaccines that have entered the market since Guidelines were published (eg, canine influenza virus strains H3N8 and H3N2), as well as practical recommendations for dogs/cats that are overdue for a booster. Given the unprecedented number of vaccines available for use in companion animals, an additional section describing known vaccine adverse reactions, along with recommendations managing these reactions has been included.

(Given the number of new companion animal vaccines that have, and will enter, the market in 2016-2017, the AAHA Vaccine Guidelines Task Force is currently in the process of updating Canine Vaccination Guidelines…the next iteration of vaccination Guidelines is planned to be published in an online format. In this way, “real-time” updates on new vaccines and recommendations can be provided in a timelier manner.)

NOTE: Published vaccination recommendations for the dog and cat are based, whenever possible, on the results of current scientific studies. The reader is reminded, however, that for some of the recommendations offered, published studies are simply not available. Furthermore, not all recommendations published in the Canine (AAHA) and Feline (AAFP) Vaccination Guidelines fall within the manufacturers’ label recommendations.

TABLE 1: INITIAL VACCINATION of PUPPIES/DOGS CORE Vaccines Administration Booster Recommendations Combination product 3 (to 4) doses are recommended Administer a single dose (of a administered as: between 6 and 18-20 weeks of age. combination product) not later than 1 year following the last dose in the MLV or Recombinant Example: 8 weeks; and 12 weeks; initial series. Virus 16 weeks, AND, a final dose at 18 to + MLV Parvovirus 20 weeks of age. (NEW) NOTE: a minimum interval of 2 + MLV Adenovirus-2 weeks between any 2 doses of NOTE: Serologic data vaccine is recommended. (unpublished: U of Wisconsin) on OPTION: May also include young dogs (n = >1200) indicates Administer subsequent boosters MLV Canine Parainfluenza maternally derived antibody every 3 years (or longer). Virus. interferes with both Distemper and Parovirus immunization in approx. 15% dogs at 16 weeks of age. (all dogs studied were personally owned pets examined in private practice). Rabies (killed) A single dose of is Schedule a second dose to be usually administered 12 or 16 weeks administered not later than 1 year 1-Year & 3-Year vaccines are of age. following administration of the 1st available. dose, regardless of the dog’s age at the time the initial dose is given.

Then…every 3 years thereafter.

(State/Local/Provincial law applies) (State/Local/Provincial law applies) NON-CORE Vaccines Administration Booster Recommendations B. bronchiseptica Single intranasal (IN) dose at 12 or Where risk of exposure is sustained, + canine parainfluenza virus 16 weeks of age. (optional-some administer a single dose 1 year (intranasal only) authors recommended 2 doses at 12 following the last dose administered and 16 weeks of age). then every year thereafter. (some IN products may also contain CAV-2 antigen) IN vaccine may be administered as early as 3 to 4 weeks of age. B. bronchiseptica only Parenteral (SQ): Two doses are Where risk of exposure is sustained, (monovalent) required, 2 to 4 weeks apart. administer a single dose 1 year Intranasal (IN): The manufacturer following the last dose administered, Three (3) options are recommends a single initial dose. then every year thereafter. available: Intraoral: The manufacturer > Parenteral (killed-bacterin) – recommends a single initial dose. or- > Intranasal (avirulent live) -or- > Intraoral (avirulent live).

Leptospirosis 2 initial doses, 2 to 4 weeks, are Where risk of exposure is sustained, (killed) 4-serovar required regardless of the dog’s age. administer a single dose 1 year following completion of the initial NOTE: routine use of a 2- NOTE: it is not recommended to 2-dose series, then every year serovar vaccine is administer the 1st dose prior to 12 thereafter. not recommended. weeks of age.

NOTE: Small Breed Dogs (< 20 pounds): consider delaying initial doses until the CORE vaccine series has been completed. 2 initial doses, 2 to 4 weeks, are Where risk of exposure is sustained, (recombinant or killed or required regardless of the dog’s age. administer a single dose 1 year Chimeric/Recombinant following completion of the initial crLyme) 2-dose series, then every year thereafter. NOTE: Small Breed Dogs (<20 pounds): consider delaying initial OPTION: For dogs residing in doses until the CORE vaccine series endemic regions, administration of has been completed. the first booster 6 months following completion of the initial 2-dose series is a reasonable alternative schedule. An additional booster is recommended at 1 year following completion of the initial series with annual vaccination recommended thereafter.

Canine Influenza Virus (H3N8) 2 initial doses, 2 to 4 weeks apart are Where risk of exposure is sustained, (killed) required. administer a single dose 1 year -and- following completion of the initial 2-dose series, then every year Canine Influenza Virus (H3N2) thereafter. (killed)

NOTE: Canine coronavirus vaccination is not recommended. NOTE: Crotalus atrox (Western Diamondback rattlesnake) vaccine should only be used in dogs with a defined risk for exposure. Follow the manufacturer’s recommendations for dosing.

Overdue for Vaccination Studies focused on dogs that are overdue for routine vaccination have not been published. The following recommendations represent expert opinion and are intended to provide a practical approach to immunizing dogs when conventional vaccination guidelines have not been followed:

Overdue during the initial vaccine series: While most practices administer the initial core vaccine series to young dogs at intervals of 3 to 4 weeks, dogs exceeding a 6-week interval between any of the initial doses should receive 2 additional doses, 3 to 4 weeks apart.

The same is true during the initial 2-dose series recommended for dogs receiving non-core vaccines. If the interval between doses exceeds 6 weeks, 2 additional doses, 3 to 4 weeks apart should be administered.

Overdue for CORE vaccine booster: administer a single dose of a combination core vaccine regardless of the number of years that have lapsed.

Overdue for RABIES booster: requirements for re- that are overdue for a rabies booster vary from State to State, and may vary within an individual State. Many States follow recommendations published in the 2016 Rabies Compendium that states: administer a single dose, after which the dog will be considered immediately immunized. NOTE: the Rabies Compendium, as published by the Natl Assoc. of State Veterinarians, Inc., is NOT a legal document. Veterinarians must be familiar with rabies immunization requirements and laws within the State, local jurisdiction, or Province in which they practice.

Overdue for Leptospirosis, Lyme and/or parenteral Bordetella booster: dogs that are within 2 years of a previous dose may receive a single dose. Dogs exceeding a 2-year interval should re-start the initial 2-dose series.

Overdue for intranasal or intraoral Bordetella booster: administer a single dose regardless of the number of years that have lapsed.

Overdue for Canine Influenza Virus booster: dogs that are within 2 years of a previous dose may receive a single dose. Dogs exceeding a 2-year interval should re-start the initial 2-dose series.

TABLE 2: INITIAL VACCINATION of CATS/KITTENS

CORE Vaccines Administration Booster Recommendations MLV Panleukopenia + 3 doses are recommended between 8 Administer a single dose (of a MLV Herpesvirus + and 16 weeks of age. combination product) not later than 1 MLV Calicivirus year following the last dose in the Example: initial series. NOTE: 2015 WSAVA and the 8 weeks; and 12 weeks; and European Advisory Board on 16 weeks of age… an additional Cat Diseases (2015) dose at 20 weeks of age may be Administer subsequent boosters every recommend avoiding use of recommended where risk of 3 years. killed (adjuvanted) vaccines exposure is high. when implementing vaccination protocols for cats. Recombinant Rabies Single dose is usually administered Schedule a second dose to be [non-adjuvanted] at 12 or 16 weeks or age. administered not later than 1 year following administration of the 1st Now available as a 1-Year dose, regardless of the cat’s age at product and a 3-Year product. the time the initial dose is given.

-or- Then…every 3 years thereafter.

Killed Rabies [adjuvanted] (State/Local/Provincial law applies) (State/Local/Provincial law applies) Available as 1-Year & 3-Year products.

NON-CORE Vaccines Administration Booster Recommendations Recombinant Feline Leukemia Recommended for all kittens: Where risk of exposure Virus (rFeLV) Administer 1 dose as early as 8 exists…administer a single dose [non-adjuvanted] weeks of age followed by a 2nd dose annually thereafter. 3-4 weeks later. Booster 1 year later. -or- The Au recommends 2 doses at 12 (some authors recommend and 16 weeks of age followed by a revaccination every 2 or 3 years for Killed Feline Leukemia Virus booster 1 year after completion of cats considered to be at “low risk” for [adjuvanted] the initial series. exposure). Killed Feline 3 initial doses, 2 to 4 weeks apart, if The manufacturer recommends Immunodeficiency Virus (FIV) indicated. annual boosters where risk for exposure is sustained. [Only available as a Killed- adjuvanted product] NOTE: vaccination can cause a False + FIV test result lasting for (This product was removed NOTE: cats receiving this vaccine several years. Kittens having nursed from the US and Canadian should be ‘microchipped’ to from a vaccinated cat may also have markets in 2016) facilitate identification if the cat a False + test result if tested prior to becomes lost and is presented to an 6 months of age. animal shelter or veterinary practice. Currently, there is no commercial test that has been shown to reliably distinguish a vaccinated from an infected cat. Feline Bordetella A single intranasal (IN only) dose Booster annually where the risk of bronchiseptica administered as early as 4 weeks of exposure is present. age, if indicated. Avirulent Live Intranasal NOTE: indications for use of this (non-adjuvanted) vaccine are limited. Chlamydia felis 2 initial doses 3 to 4 weeks apart, if Booster annually where exposure risk (formerly: Chlamydophila indicated. is sustained. felis and Chlamydia psittaci)

(both non-adjuvanted and Indications for use of this vaccine are adjuvanted products are limited. available) Virulent Systemic (VS) 2 initial doses 2 to 4 weeks apart, if The manufacturer recommends Calicivirus indicated annual vaccination where exposure risk is sustained. Killed-adjuvanted Disease prevalence is considered low, even within high-density housing environments (eg, shelters).

Indications for use of this vaccine are limited.

NOTE: Unless specifically indicated for intranasal administration, all feline vaccines should be administered by the SQ route. NOTE: The Feline Infectious Peritonitis (FIP) vaccine has been re-categorized as NON-Core, but is still not recommended by most authors due to limited or no known efficacy. NOTE: The World Small Animal Veterinary Association (Vaccine Guidelines Group) does not recommend administration of either the FIP vaccine on grounds of low to no demonstrated efficacy. NOTE: Inactivated (killed), adjuvanted vaccines are recommended for administration to: 1. Pregnant queens, and 2. Retrovirus (FeLV or FIV) infected cats (no studies have been published that define the risk of administering MLV or recombinant vaccines to retrovirus + cats).

Overdue for Vaccination Studies focused on cats that are overdue for routine vaccination have not been published. The following recommendations represent expert opinion and are intended to provide a practical approach to immunizing cats when conventional vaccination guidelines have not been followed:

Overdue during the initial vaccine series: While most practices administer the initial core vaccine series to kittens at intervals of 3 to 4 weeks, cats exceeding a 6-week interval between any of the initial doses should receive 2 additional doses, 3 to 4 weeks apart.

The same is true during the initial 2-dose series recommended for cats receiving non-core vaccines. If the interval between doses exceeds 6 weeks, 2 additional doses, 3 to 4 weeks apart should be administered.

Overdue for CORE vaccine booster: ASSUMING USE OF A MODIFIED-LIVE VIRUS VACCINE, administer a single dose of a combination core vaccine regardless of the number of years that have lapsed.

Overdue for RABIES booster: requirements for re-vaccination of cats that are overdue for a rabies booster vary from State to State, and may vary within an individual State. Many States follow recommendations published in the 2016. Rabies Compendium that states: administer a single dose, after which the cat will be considered immediately immunized. NOTE: the Rabies Compendium, as published by the Natl Assoc. of State Public Health Veterinarians, Inc., is NOT a legal document. Veterinarians must be familiar with rabies immunization requirements and laws within the State, local jurisdiction, or Province in which they practice.

Overdue for Feline Leukemia booster: this is complicated…compared to kittens, adult cats are significantly more resistant to developing progressive disease associated with FeLV . For this reason, significant differences of opinion exist with respect to conventional intervals (annual, biennial, triennial recommendations exist). It would be reasonable to recommend that the initial 2-dose series should be restarted in the event a cat is more than 3 years overdue for vaccination.

References:

1. Srivastav A, Kass PH, McGill LD, et al. Comparative vaccine-specific and other injectable-specific risks of injection-site sarcomas in cats. J Am Vet Med Assoc. 241: 597-602, 2012.

2. Greene CE and Levy JK. Immunoprophylaxis. Capt 100, in CE Greene (ed): Infectious Diseases of the Dog and Cat. 4th Ed. Elsevier-Saunders, St Louis, pp. 1163-1205, 2012.

3. Moore GE and HogenEsch H. Adverse vaccinal events in dogs and cats. Vet Clin N Am: Small Anim Pract 40:393-407, 2010.

4. Moore GE, Guptill LF, Ward MP, et al. Adverse events diagnosed within three days of vaccine administration in dogs. J Am Vet Med Assoc. 227:1102–1108, 2005.

5. Ford RB. Feline injection-site sarcoma: then and now. Today’s Vet Pract 3:54-57, 2013.

6. Moore GE, DeSantis-Kerr AC, Guptill L, et al. Adverse events after vaccine administration in cats: 2,560 cases (2002-2005). J Am Vet Med Assoc. 231:94-100, 2007.

7. Ford RB: Vaccine adverse events: acute allergic angioedema. Today’s Vet Pract 3(1):53-55, 2013.

8. Day MJ et al. A kinetic study of histopathological changes in the subcutis of cats injected with non-adjuvanted and adjuvanted multi-component vaccines. Vaccine. 2007

9. Shaw SC, Kent MS, Gordon IK, Collins CJ, Greasby TA, Beckett LA, Hammond GM, Skorupski KA. Temporal changes in characteristics of injection-site sarcomas in cats: 392 cases (1990-2006). J Am Vet Med Assoc. 234:376-80, 2009.

10. Day MJ, Horzinek MC, Schultz RD and Squires RA. Guideline for the vaccination for dogs and cats. J Sm Anim Pract. 57: E1-E45, January 2016.

11. Hartmann K, Day MJ, Thiry E, et al. Feline injection-site sarcoma: ABCE guidelines on prevention and management. J Feline Med Surg. 17(7):606-613, 2015

Updated January 2017